Crash when Exchanging voices

When editing a score imported from MIDI file, program repeatedly crashes when trying to exchange voices in a particular measures. Sometimes it can be worked around by copying the measure contents to another measure, editing there and then copying back.

Frequency: always
Steps to reproduce: Open attached score, go to measure 6 and select it. Then select "Edit...Voices...Exchange Voice 1-2".
Result: Program immediately crashes and gives the following error message on the console:

sbesch@Dagoba:~/mscore
Suspending PulseAudio
no JACK server found
exchange voice 0 1, tick 7200-8640, measure 0x5a06840-0x5a08d10
WARNING: Child process terminated by signal 11

In fact, when editing this file the program crashes so frequently at random times (moving cursor, adding notes, deleting notes) and also refuses to delete notes or enter notes in certain voices, that this score sample should be an excellent "bug" exposer.

OS: Ubuntu Hardy
CPU: Intel Quad Core, 2.4 GHz
Memory: 8-GB
MuseScore Version:0.9.5 R1827